1. Technical Field
The present disclosure relates to wireless communication, and particularly to a radio frequency (RF) front-end circuit for multiband wireless communication devices.
2. Description of Related Art
Many wireless communication devices, such as mobile phones, personal digital assistants (PDA), and notebook computers, utilize multiband wireless communication. In use, such devices receive and transmit wireless signals in different frequency bands, such as Global System for Communications (GSM) and Universal Mobile Telecommunications System (UMTS).
Most multiband wireless communication devices are enabled to receive and transmit wireless signals in different frequency bands using their RF front-end circuits. An RF front-end circuit of a multiband wireless communication device generally includes a multiband antenna, an antenna switch, and a plurality of signal processing circuits, such as amplifier, filter, duplexer, for example. The multiband antenna can receive and transmit wireless signals in a plurality of frequency bands. The antenna switch is connected to the multiband antenna and includes a plurality of pins for respectively transmitting the wireless signals in the plurality of frequency bands. The signal processing circuits are correspondingly connected to the pins. The antenna switch can selectively connect any of the signal processing circuits to the multiband antenna using the pins.
In use, when the multiband wireless communication device needs to receive or transmit wireless signals in any frequency band selected from the plurality of frequency bands, the antenna switch connects signal processing circuits for wireless signals in the selected frequency band, such as a filter for received wireless signals, and an amplifier for amplifying outgoing wireless signals in the selected frequency band, to the multiband antenna using pins corresponding to these signal processing circuits. Thus, RF channels for transmitting the wireless signals in the selected frequency band are generated in the antenna switch. Through the RF channels, wireless signals in the selected frequency band received by the multiband antenna can be transmitted to a corresponding signal processing circuit to be processed, such as transmitted to the filter to be filtered, and wireless signals in the selected frequency band processed by another corresponding signal processing circuit, such as amplified by the amplifier, can be transmitted to the multiband antenna to be sent.
A main shortcoming of many RF front-end circuits is that the antenna switches may generate additional costs. For example, an antenna switch of a conventional RF front-end circuit generally includes different pins for respectively transmitting wireless signals in different UMTS frequency bands. However, most multiband wireless communication devices use only one of the UMTS frequency bands, whereby the pins for transmitting wireless signals in unused UMTS frequency bands unnecessarily increase costs.
Therefore, there is room for improvement within the art.